I Guessed

However, because Xu Feiyang knew how to handle things, he also knew how to judge people. He knew that Nuannuan was not as harmless as she appeared, so he apologized to her every time, punished his subordinates, and made amends to her.

Those few encounters were not enough for Nangong Nuannuan to investigate his background.

She only knew a bit of superficial information.

The Xu family wanted to harm Xu Feiyang. Xu Feiyang had suffered a great loss and narrowly escaped death a few times. In the end, in a fit of anger, he destroyed the Xu family.

Why had the Xu family adopted Xu Feiyang in the first place?

Nangong Nuannuan did not believe in the Xu family adopting a pitiful baby lying by the roadside.

There were so many abandoned orphans in the orphanage. Why had the Xu family not adopted one or done some charity work instead to gain good karma?

Since the Xu family had never done any charity work, why did they bring Xu Feiyang back home?